Redmine

Sorry but the underlying issue seems to be a Ruby Regexp one as Redmine code in SearchHelper#highlight_tokens seems fairly safe in the way it handles case : source:trunk/app/helpers/search_helper.rb#L22.

Added #4050 as blocker.

Actually, I made a fix

module SearchHelper
  def highlight_tokens(text, tokens)
    return text unless text && tokens && !tokens.empty?
    re_tokens = tokens.collect {|t| Regexp.escape(t.mb_chars.downcase)}
    regexp = Regexp.new "(#{re_tokens.join('|')})" 
    result = ''
    position = 0
    text = text.mb_chars
    text.downcase.split(regexp).each_with_index do |words, i|
      if result.length > 1200
        # maximum length of the preview reached
        result << '...'
        break
      end
      words = text[position ... (position + words.size)]
      position += words.size
      if i.even?
        result << h(words.length > 100 ? "#{words.slice(0..44)} ... #{words.slice(-45..-1)}" : words)
      else
        t = (tokens.index(words.downcase) || 0) % 4
        result << content_tag('span', h(words), :class => "highlight token-#{t}")
      end
    end
    result
  end
end